A conventional computer mouse functions both to track a position across a graphical user interface (GUI) and to input commands into the computer, usually relating to a word, icon, or text section on which the tracking system was located at the time of the input command. A conventional computer mouse requires power that typically comes from one of two sources. In a first “wired” form, a power cord tethers the mouse to the computer, thereby providing power for both the tracking function and the input command function, while also providing a signal path for both the position tracking system and the input command. The power cord, however, restricts freedom of movement for the user. In a second “wireless” form, an on-board power source such as a battery provides power for these functions. The signals for both the tracking and input command functions are transmitted through free space in the form of RF signals. An on-board power source, however, requires constant recharging or replacement.
A technique for powerless position tracking is disclosed in U.S. patent application Ser. No. 11/111,444 entitled “Position Determination Utilizing a Cordless Device” filed on Apr. 21, 2005. The pointing device disclosed therein has a reflector and interfaces with a computer system having a light source, an image collection system, a processor, and a graphical user interface (GUI). The light source generates a light signal and the reflector within the pointing device reflects a portion of the light signal back to the image collection system, which correlates a position of the reflector to a position on the GUI. The correlation is continuously updated by a processor. Because a reflector is a passive element that does not require any power, a pointing device that utilizes a reflector does not need to be tethered to a computer system or equipped with a battery. Because the “point and click” functions are so tightly interrelated when used in conjunction with a GUI, it is desirable for the “pointing” and “clicking” functions to be integrated into a single powerless device.